On the basis of the hypothesis that vascular pathology is of etiological importance in ozena, the microcirculation of 127 persons, with and without nasal diseases, was investigated by biomicroscopy of the conjunctiva and the nailbed. Ischemia and the pattern described in acrocyanosis were common features found in primary atrophic rhinitis and ozena. There was good correlation between the severity of the vascular pathology and the degree of nasal atrophy.